Investigation of Mo-, Pt-, and Rh-doped rutile TiO2 based on first-principles calculations

Abstract

In the present research, we use a first principles calculation to investigate the electronic structure and optical properties of Mo-, Pt- and Rh-doped rutile TiO2. The results indicate that the band gap of the Mo-, Pt-, and Rh-doped systems decreases to 1.758, 0.906, and 0.971 eV, respectively, compared with the 1.968 eV band gap of intrinsic TiO2, which is due to the hybridization of the doped atom d and O p orbital electrons, resulting in the formation of an impurity level and enhanced conductivity. The charge-difference density maps show that the covalence is enhanced in the region around Ti atoms for Mo- and Pt-doped systems, whereas Rh doping has little effect on the covalence. Based on these results, the bond population is 0.42, 0.28, and 0.27 for Mo-O, Pt-O, and Rh-O bonds, respectively. In the absorption spectrum, the peaks of the doped systems decrease significantly and redshift. Compared with the Mo-doped system, the Rh- and Pt-doped systems have lower static dielectric constant and dielectric loss in the low-energy region, which is promising for fascinating applications in microelectronic components.